Having read through the extent of Seaworthy's concern with the two versions of the double sheet bend (along with all of the relevant insight), I was very interested to learn more about devising an inexpensive and straightforward way of testing knots. Xarax went into some detail concerning the use of a long ram hydraulic bottle jack with pulleys mounted on either side. I must confess that I am having difficulty envisioning exactly what he is describing.
Does anyone have a photo or a link to such a device? Or perhaps something along the same line?